Mailpiece creation systems such as mailpiece inserters are typically used by organizations such as banks, insurance companies, and utility companies to periodically produce a large volume of mailpieces, e.g., monthly billing or shareholders income/dividend statements. In many respects, mailpiece inserters are analogous to automated assembly equipment inasmuch as sheets, inserts and envelopes are conveyed along a feed path and assembled in or at various modules of the mailpiece inserter. That is, the various modules work cooperatively to process the sheets until a finished mailpiece is produced.
A mailpiece inserter includes a variety of apparatus for conveying sheet material along the feed path. Commonly, a roller assembly, comprising opposed driven and idler rollers, is employed to perform this principal function. The opposed rollers form a conveyance nip to capture the face surfaces of the sheet, or stack of sheets, and drive the material along the feed path.
While roller assemblies of the prior art have proven successful and reliable for conveying a single sheet of material or a small stack of sheet material, e.g., less than five (5) stacked sheets, difficulties are encountered when conveying a large stack of sheets, e.g., a stacked collation of sheet material consisting of ten (10) or more sheets. That is, when transporting a large stack of sheet material, the roller assembly shingles the stacked sheet material, i.e., a condition wherein the edges of the stacked sheets become misaligned. Inasmuch as the stacked sheet material is no longer in register, an additional processing step may be required to align the edges before subsequent operations. For example, a stacked sheet material collation should be registered before stitching or stapling operations. Similarly, it may be necessary to align the edges to insert the stacked sheet material into a mailing envelope.
A need, therefore, exists for a roller assembly which accurately and reliably conveys stacked sheet material while maintaining edge registration thereof.